


Two is the one for me

by acidpop25



Series: Love Times Two [1]
Category: Avengers (Comic), Marvel, Marvel 3490, The Avengers (2012)
Genre: Alcohol, Alternate Universe - Twins, Eiffel Tower, F/M, First Time, M/M, Multi, Polyamory, Siblings, Threesome - F/M/M
Language: English
Status: Completed
Published: 2011-12-12
Updated: 2011-12-12
Packaged: 2017-10-27 06:36:32
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,281
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/292704
Author URL: https://archiveofourown.org/users/acidpop25/pseuds/acidpop25
Summary: <blockquote class="userstuff">
              <p>"What my darling brother means is that he’d like a threesome." AU where Tony has a twin sister.</p>
            </blockquote>





	Two is the one for me

**Author's Note:**

> No actual incest in this fic– both Tony and Natasha are with Steve, but not with each other.

“Seriously,” Clint demands under his breath, “why did there have to be _two_ of them?”

Steve doesn’t reply, but he can’t help but sympathize with the sentiment. Tony and Tasha are exchanging rapid-fire tech talk across the table at top volume, and while it probably means the Avengers will end up with jetpacks or something in the long run, right now it’s giving Steve a headache. He clears his throat.

“If there’s nothing else,” he starts, and there’s a general murmur of agreement and subsequent hasty escape by the rest of the team. The Stark twins remain where they are, both bent forward toward each other with an almost palpable air of excitement, eyes bright. They seem more like identical twins than fraternal, like one person split in two bodies, and looking at one is like looking at the other through a funhouse mirror, the same appearance distorted to the opposite sex. It’s a little unsettling, but mostly because it tends to make Steve’s insides knot up in a way they really shouldn’t.

He leaves them to it– sooner or later they’ll realize that they aren’t in their workshop and move along, and it’s easier to let time take care of it than to try and interrupt them. Maybe he’ll drop by later and force some food on them, make sure they haven’t blown themselves up– the usual hazards of their fits of genius. He doesn’t quite know how Miss Potts has put up with them for all these years.

\---

Neither Tony nor Tasha has surfaced from the workshop by the time ten o’clock rolls around and Steve decides to intervene. He makes them both sandwiches– turkey on rye (mayo but no mustard) for Tash, and ham and cheese (but not swiss) for Tony. _Is it weird that I know that?_ Steve wonders distractedly as he heads down the stairs. Metallic banging sounds reach his ears even through the closed workshop door, and Steve juggles the food briefly to punch in the entry code and go inside.

“Hey, Steve,” Tasha says without looking up. She’s sitting perched on a stool with her feet hooked into the rungs, squinting at a tiny, fiddly assembly of wires through a magnifier. The source of the noise is Tony, who is working on– well, on something. Some sort of chassis, maybe. He’s muttering from underneath it.

“Hi. I, uh, brought you guys dinner.”

“We’re fine!” Tony calls from under the metal, and Steve represses the urge to roll his eyes.

“You’ve been down here since three.”

“What time is it now?” Tasha asks, and Jarvis answers before Steve can– “Ten oh five, Miss Stark.”

“Really? Huh.” She frowns down at the wires. “Okay. Set it on the workbench, I can’t put this down right now.”

Steve complies and then drags one of the chairs over next to her. “Is it explosive?”

Tasha smirks. “Maaaaaybe.”

“Tasha.”

A full-fledged grin, now. “No, not unless Tony and I wildly miscalculated, which we never do, because we are geniuses. But if I set it down I’ll lose my place and have to start over, probably, and poof, there’s an hour down the drain and an impatient sibling dogging my every move and never letting me hear the end of it, as if _he_ hasn’t ever done equally stupid shit, am I right? Fine work is my gig, I have smaller hands.”

“You’re a delicate flower,” Tony retorts, and Tasha sticks her tongue out. It looks reflexive, probably left over from when they were kids.

Steve stays quiet, watching them work. Well, watching Tasha, since Tony is half-hidden, mostly just a pair of oil-smeared jeans and muffled blue glow. She _does_ have very precise hands, slender and long-fingered and possessed of excellent fine motor control. Steve likes watching her work, quiet and concentrated and in her element.

“I think it’s done,” she says at last, prodding at one of the wires and then carefully laying it aside. “You said you brought dinner?”

“It’s just a sandwich,” Steve says with a shrug, but Tasha tears into it contentedly, hungry even though she’s used to ignoring her body’s needs. Eventually, Tony surfaces as well, wiping off his hands and moving to inspect his twin’s efforts.

“Tony,” Steve says, “eat.”

“I’m fine.”

“Tasha is eating,” Steve replies. He always feels like pitting them against one another is cheating, but it’s fairly foolproof– Tony relents with a sigh.

“You seriously just came down here to feed us sandwiches?” Tony asks around a mouthful of food. Steve shrugs.

“And to make sure you hadn’t blown yourselves up.”

“Oh, Jarvis monitors that.”

“I know.”

“Aww, Steven, were you _worried_ about us?” On cue, Tasha pauses eating to look up at Steve from under her eyelashes. They’re very lush eyelashes, and very pretty eyes. Steve can feel his cheeks flushing.

“You two don’t take care of yourselves,” he deflects, crossing his arms. “You don’t even take care of each other, you just encourage your bad habits.”

Tasha’s head snaps up suddenly, and there’s no flirtation in her expression now. She’s glaring, narrow-eyed. “Well, you’ve done your duty saving us from ourselves,” she says waspishly, “you can go now.”

“Tasha, I didn’t mean–”

“I said _go_.”

Her posture has gone tense and angry, and when Steve glances to Tony he finds no ally there– Tony’s expression has gone cold and closed-off.

Steve is a soldier; he knows the wisdom of tactical retreats.

\---

“You know he didn’t mean it like that.”

Tasha huffs and curls into a ball against her brother’s side. “Sure. So do you. That doesn’t make it okay.”

Tony pulls a face, because she’s not wrong. He and Tasha do have a set of awful overlapping habits, and they do both only encourage each other. But they always, _always_ take care of each other, and being told otherwise made Tony want to hit things and drink too much. He’s working on the latter, and Tasha is keeping pace with him, sleepy and unhappy. Tony reaches out a hand to settle on her neck, touching the arc reactor at the base of her skull. His keeps his heart beating; hers, hidden under her thick hair, is what keeps her brain working. Her smart, amazing, wonderful brain.

“Another drink?” Tony asks rhetorically. He pours her one, watches her throat work as she tosses it back.

“More. I’m emotionally unstable right now, encourage my bad habits.”

“Oh, babe,” Tony says, but obliges her anyway. “You’re gonna be so hungover.”

“I’m cool with that.”

“I know.”

They fall into silence; Tasha will eventually drink herself into exhaustion and fall asleep in Tony’s bed. He’ll make an uncoordinated effort to get her out of her jeans and then join her not long after, crashed out with his face mashed into the pillow while she snores next to him. Tasha only snores when she’s been drinking.

\---

Tony is unpleasantly jarred into consciousness by an alarm going off and the sound of his sister throwing up in the bathroom. Wonderful.

“Tasha?”

“No fucking way!” she groans, and Tony takes that as his cue to to handle things. He feels like shit, but Tasha is smaller and can’t take alcohol quite as well, so if he feels like shit then she probably feels like letting the latest emergency end her suffering sounds like a good idea. Tony goes for his suit.

“Iron Man!” Thor bellows, and jesus, Tony needs to think about adding noise cancellation into his helmet, “Where is thy fair partner?”

‘Hung over beyond recognition’ is probably not the thing to say, so he goes with, “Not feeling well. I can handle it.” Since “it” turns out to be an army of homicidal robots, no one really has time to ask him any more questions.

By the time they’re done saving the world, Tony feels ready to keel over and mostly just wants to go check on his sister and go back to bed, so of course, of _course_ Steve corners him before he can make an escape.

“Hey, uh. Listen, Tasha, is she... is she okay?”

“Fine,” Tony replies shortly. “I’d like to check on her, you know, try out that whole ‘taking care of each other’ thing, so if you don’t mind...” He gestures toward the hallway which Steve is blocking. It’s nasty and petty, but Tony _is_ nasty and petty. It should feel good. It only sort of does.

Steve stammers something as he moves aside, but Tony isn’t listening.

\---

“Tony?” Steve’s voice is quiet and his gaze on Tasha, who is drowsing in Tony’s bed. “Can I come in?”

“Knock yourself out.”

Steve frowns a little and creeps quietly inside. “How is she?”

“It’s just a hangover, Steve. Nothing life-threatening.”

“Oh.” He frowns, disapproving or disappointed, but schools his expression quickly. “So, uh. What are you working on?”

“Jet designs.”

“Right.” There’s an uncomfortable silence. “Listen, Tony.”

“Spit it out, Steve,” comes Tasha’s voice. She drags herself into a sitting position, sheets draped over her lower body for the sake of Steve’s delicate sensibilities– her jeans are still lying crumpled on the floor somewhere.

“I came to apologize. I didn’t mean– I know how close you two are. I didn’t mean to be hurtful.”

“I feel like I’ve kicked a puppy or something,” Tasha says. “Ugh, yes, fine, you’re sorry. I know. I drank a lot, it’s fine now.”

Steve blinks at her, and Tasha rolls her eyes and opens her arms. “Come here and hug it out, bitch.”

“It’s an expression,” Tony interjects before Steve can ask or take offense. “We’ve really gotta get you up on your modern slang, Cap.”

“So you keep telling me,” Steve agrees, and sits down on the edge of the wide bed to accept Tasha’s offered hug. She must have showered at some point because she doesn’t smell of alcohol or metal, but instead of something fruity-tart and of warm skin. Mostly like herself, and a little like Tony from sleeping in his bed. _Do they do that a lot?_ Steve wonders. _Share beds? They don’t need to, this place has a ton of bedrooms. Comfort thing, maybe?_

Tasha nuzzles into the crook of his neck, which is a little startling. “You’re very warm, did you know that? You throw heat like a furnace.”

“I run hot. Side effect of the serum.”

“ _Yeah_ you do,” Tony agrees with a leer. Steve blushes furiously and lets go of Tasha, because there’s got to be some kind of etiquette against snuggling a man’s twin sister in his bed while that same man is flirting with you. Even in the future.

“Shy boy,” Tasha says with a note of complaint, flopping back on the pillows. “I was enjoying that.”

“Me too,” Tony agrees, and Steve snaps his head back and forth between the two so fast he thinks he might have given himself whiplash.

“Um?”

“What my darling brother means is that he’d like a threesome,” Tasha explains, stretching. It’s hard to decide if she’s serious or not when she moves like that, it’s bad for Steve’s lucidity. “You _do_ have a thing for us, don’t you? I’ve definitely caught you checking him out.”

“That’s not– there are so many problems with what you’re saying.”

“We’re all consenting adults here.” Tony puts in.

“She’s your _twin_.”

“Well, yes, which is why I’m okay with you thinking she’s as hot as me. She is, it’s cool. We’ve got great genes.” Tony looks amused, Tony _always_ looks amused. It’s as annoying as it is sexy. “Unless the problem here is that I’m a guy? Are there repressed 40’s sexual hangups here? Because I can help you fix them. With my dick.”

“ _Tony_ ,” Steve says, sounding pained. His face and neck are bright red.

“Does that blush go all the way down?” Tasha asks him, and kicks off the sheets. She’s only wearing a pair of lacy blue panties with her tank top, and Steve– Steve might be a super soldier, but in this he’s only human. It’s probably for the best that he doesn’t catch Tony’s victory fist pump when Tasha draws him down to the bed, though.

“I don’t really... have much experience,” he warns them, and Tasha grins up at him, delight crinkling the corners of her eyes.

“You couldn’t have better teachers. We’ll make you feel so good, baby.” She leans up and kisses him deep and thorough, taking her time, and Steve pulls her up to press against him, a hand on her waist and the other at the nape of her neck.

He pauses, breaks the kiss. “What’s–?”

“You never noticed it?” she asks, and lifts her hair, exposing the arc reactor. “Did Tony never tell you why he has his?”

“I never asked.”

“Another time then, it’s not a fun story. But yeah, I’ve got one as well. Can we get back to making out?”

“No,” Tony says, “I want a turn. Sharing is caring, sis.”

“Like you know how to share,” she retorts, but gives Steve a gentle shove in her brother’s direction. Kissing Tony... actually isn’t that much different, except for the bristles of his goatee. He’s broader and not so softly curved as a woman, but he’s just as eager and passionate as Tasha and Steve has _wanted_ this, thought about it even though he still feels a little weird about doing so. Steve slides a hand up under Tony’s shirt; his fingers catch on scar tissue, graze the edge of the arc reactor. Tony makes a sound in his throat.

“You really need to be naked.”

“Only me?”

“Touché, my captain,” he replies, and starts stripping off his clothes. Steve only realizes he’s staring when Tasha gives his shirt a pointed tug and he gets with the program.

“Ooh wow,” she says appreciatively. “I knew you were gorgeous, but goddamn.”

“Thanks.” He’s blushing again. “You’re, you’re lovely too.” He darts a glance to Tony. “Both of you.”

Tony clambers on to the bed and brackets Steve’s hips with his hands. “I really want your dick in my mouth right now, if that’s okay by you.” He takes Steve’s breathless, involuntary “ _oh_ ” as the assent it is and bends down. Steve groans and tries very hard not to grab Tony and urge him on, twisting his hands in the sheets instead.

“Huh,” Tasha remarks, “he’s good at that.” She says it in much the same tone she might use to comment on the weather, but then she pulls off her tank top and Steve’s brain short-circuits again. Tasha settles half on top of him, kissing her way along his jaw and down his neck and letting Steve touch all he wants.

“Oh God,” he groans, “Tony, please, I’m going to–”

Tony doesn’t let him, though, and Steve could sob with frustration when he pulls away.

“Hey, shh, calm down. I have better ideas for you.” Tony kisses the hollow of Steve’s hip, then crawls up his body. “Tasha, lube and condoms please?”

“I thought you’d never ask.” Steve hears her rustling around in the nightstand, but he’s mostly occupied with an armful of Tony, who has gotten their hips lined up and is rubbing against him.

“Earth to Anthony,” Tasha says, and hands him a bottle. Tony draws back a little, enough to meet Steve’s eyes.

“If you’re not into this, or it’s too much, or you want to stop for whatever reason, tell me. Okay? This is supposed to be fun for you.”

Steve nods. “Okay. I trust you.”

Tony stares for a moment, then kisses Steve again, fiercely. “I don’t know what the hell I did to deserve you,” he rasps.

“You were you,” Steve says, and pets a hand through his hair. Tony and Tasha exchange glances Steve can’t read, then Tony smiles a little and ducks his head.

“Never change, Steve,” Tasha murmurs fondly. “Also, turn over.”

He obliges, getting up on hands and knees, and she wriggles into the space under him while Tony probes with slick fingers, working Steve’s body open. The sensation is alien but not unpleasant, and Tasha is occupying most of his attention with her soft lips and dewy skin.

“May I?” Steve asks, fingers skimming over her panties, and she nods.

“You can tear them off if you want, for all I care.”

“Christ, Tasha, don’t _say_ things like that,” he groans, and she grins up at him, unrepentant. Cheeky creature. Just for that he does rip them, and her breathing comes a little heavier.

“Touch me,” she murmurs. “Come on, Steve.”

“How do you want me to?”

“Like this.” They shift so Steve can brace his weight on one arm, leaving the other free for Tasha to guide him. She’s slick and warm and makes amazing little whimpery moans when he gets it right, and Steve is so caught up in her that he almost forgets what Tony is doing to him– until Tony touches him just _right_ somehow and makes Steve see stars.

“Do that again,” Steve gasps, pushing back against Tony.

“You looks so hot like this,” Tasha tells him in a murmur, right next to Steve’s ear. He’s flushed and desperately turned on, sweating like he seldom does in combat. Tasha ruffles his hair and kisses him gently, and Tony echoes the motion at the small of Steve’s back. Just a brush of lips.

“Steve? Hey.” Tony nudges him. “Are you ready for me?”

“I think so. You can probably see better than I can.”

Tony huffs a laugh. “I think you are too.” He withdraws his fingers and gives Steve a playful smack on the ass, distracting Steve from the sudden lack.

Tony pushes a startled groan out of Steve when he finally presses in, but Tasha is watching his face and there’s no trace of pain there; Tony had been careful, and Steve’s body can take a lot in any case.

“That feels...”

“Full?” Tony suggests, and Steve smiles a little.

“Yeah.”

“I’d like in on that,” Tasha remarks, producing a condom packet and tearing open the foil, “if Steve would be so kind.”

Steve has to bite back several obscenities and just nod at her, let Tasha do the work of getting the condom on and lining them up. It’s Tony who pushes him into her, though, with a well-timed thrust of his hips.

“Oh _fuck_ ,” Tasha gasps, and curls her legs around Steve’s waist. “You’re so big, God, you feel _amazing_.”

He drops his head to her shoulder, overwhelmed by sensation and unable to decide if he wants to thrust forward or back. Tony ends up deciding for him, rocking forward and managing to coax them into a semblance of rhythm. He bites at the slick skin of Steve’s shoulder, just enough to sting, and Steve swears under his breath and jerks.

“Yeah,” Tasha breathes, “harder, none of us will break.”

“I can do harder,” Tony agrees, and suits action to word. If Steve had thought Tony’s mouth felt good, it’s absolutely _nothing_ compared to this, and he privately thanks his lucky stars that his superhuman stamina apparently extends to sex. It still ends pretty quickly, though, with the three of them collapsed in a sticky, breathless heap.

“I can’t believe I just did that,” Steve mumbles against Tasha’s skin. “I can’t believe the two of _you_ just did that.”

“It’s not like we banged each other.”

“She’s right,” Tony agrees, and carefully pulls out of Steve. “We just made you the very lucky filling in a Stark sandwich.”

“We just popped the cherry of a national icon. With a _threesome_.”

They high-five each other over Steve’s back, but he’s too boneless and content to call them on it.


End file.
